Multivitamins during pregnancy linked to lower rates of autism with intellectual disability

Mothers who regularly took multivitamins during pregnancy were significantly less likely to give birth to children with autism and a co-occurring intellectual disability, according to new research out of Drexel University.

The research team at the A.J. Drexel Autism Institute analyzed data collected over more than a decade in Stockholm, Sweden, finding that the 30 percent decline in risk was specifically linked to autism with attached intellectual disabilities. There did not appear to be a similar outcome for the development of autism without intellectual disabilities.

“A potential link between supplement use during pregnancy and autism is intriguing because it suggests a possible avenue for risk reduction,” said Brian Lee, associate professor in the Dornsife School of Public Health and senior author of the study.

Funded by the National Institutes of Environmental Health Sciences, the study looked a results in children who were between the ages of four and 15 by the end of 2011 and had lived in Stockholm County for at least four years. Researchers also looked at results from siblings to offset other unseen factors in autism development.

Knowledge remains limited about the effects of a pregnant mother's diet on the likelihood of her child developing autism, according to the Drexel team, whose goal was to lay the groundwork for future research by tracking the building blocks of nutrition.

“There have been more studies in recent years about varied aspects of diet during pregnancy and autism risk involving multivitamins, iron, folic acid, vitamin D and more, but the evidence is still inconclusive,” said Elizabeth DeVilbiss, a postdoctoral researcher involved with the study. “More work needs to be done in this area to clarify these potential relationships.”

Why multivitamin use would limit the presence of autism with intellectual disability isn't entirely clear. The researchers also determined outcomes for supplemental iron and folic acid, both recommended for pregnant women, but found no positive and negative correlation with autism.

“Diet during pregnancy is complicated, and there are important factors we can’t assess with our data, such as dietary intake, dose and timing. This is clearly an area for future work," said DeVilbiss. “If there is a causal relationship, we also need to understand whether there is a critical window for exposure, and what specific nutrients and amounts may be required for protection."

The full study, published in BMJ, can be accessed here.